Touch panel is widely used in various kinds of electronic devices with screens, such as computers or electronic devices which include smart phone, TV, PDA, tablet PCs, notebook computers, machine tools with industrial display touch, integrated computers and ultra books, etc. The touch panel can be divided into a capacitive touch panel, a resistive touch panel and a surface wave touch panel etc. according to the working principle.
The capacitive touch panel functions by utilizing the induced current of a human body. When a finger touches the touch panel, the user and a surface of the capacitive touch panel form a coupling capacitor due to a body electric field, for a high frequency current, the capacitor is a conductor, a small current pass through from the contact point of the finger. The current flow out from the electrodes located in four corners of the capacitive touch panel, and the current pass through the four electrodes is proportional to the distance between the finger and four corners, the four current ratios are precisely calculated by a controller to get a position of the touch point.
All current touch panels are using ITO (indium tin oxide) glass or ITO film (i.e. formed on the glass or on the film) to form patterns of driving electrodes and sensing electrodes. But the driving electrode and sensing electrode patterns formed by the ITO glass or ITO film have the following disadvantages: on one hand, the ITO driving electrode or sensing electrode bulges on the surface of the glass or transparent film, it is easy to be scratched or peeled off, which would lead to the decrease of the production yield; on the other hand, the main material of ITO glass or ITO film is a rare metal of indium, the indium is rare, so it is costly, and the resistance or surface resistance of a large size touch ITO panel is large, which affects the signal transmission speed and results in poor touch sensitivity, thus affecting the electronic product functions, and the user experiences are poor.